1. Technical Field
The present application relates generally to imaging systems, and more particularly, to imaging systems that use a fan as part of the cooling system.
2. Background
Various types of imaging such as CT systems use a cooling system to cool the X-ray tube. The cooling system typically employs a liquid-to-air heat exchanger to remove heat from the X-ray tube during operation. The liquid cooler typically includes a fan that is used to remove heat to the ambient air. Heat exchangers are sized for the maximum steady state capable of the X-ray tube. Many X-ray systems operate at a much lower average power for which the heat exchanger is designed. The fans of such system run at a very high speed. This high speed is much higher than necessary to remove the heat generated by the X-ray tube. Such fans are noisy and have been found to be disturbing to both patients and radiologists.
It would therefore be desirable to reduce the amount of noise during operation of an X-ray system.
In one aspect of the invention the X-ray system comprises an X-ray tube temperature sensor generating a temperature signal and a fan coupled to the temperature sensor. The fan has a speed that varies in response to the temperature signal.
In a further aspect of the invention, a method for operating an X-ray system comprises measuring a temperature of an X-ray tube and controlling the fan speed in response to the temperature.
One advantage of the invention is that patient comfort is increased due to the fan operating at lower speeds when the temperatures are lower. Typically the temperatures increase slowly and thus the fan speed slowly increases which makes the corresponding increase in noise less noticeable.
Other aspects and advantages of the present invention will become apparent upon the following detailed description and appended claims, and upon reference to the accompanying drawings.
FIG. 1 is a block diagrammatic schematic view of an X-ray system having a fan control circuit according to the present invention.
FIG. 2 is a plot of fan speed with sound levels versus temperature for the system according to the present invention.